JUST about every month, a glitzy tower rises somewhere in the country, boasting the latest in “green” design and technology. To many people, that is an encouraging trend, especially when considering that commercial buildings account for more than 60 percent of the nation’s electricity consumption, according to government estimates, and generate 30 percent of all greenhouse gas emissions.

Yet these buildings represent a small fraction of the nation’s estimated 4.5 million commercial properties, many of which were erected decades ago before sustainable, or green, designs became de rigueur. This vast stock of older buildings presents a much bigger opportunity to cut down on energy consumption and carbon emissions that contribute to the warming of the planet.

Architect Vincent Callebaut’s latest project balances public galleries, meeting rooms and gathering spaces over canals and abandoned railroad tracks in the 19th Parisian district. The prototype uses green technologies and techniques but is more than just an example of sustainable design. Callebaut’s ‘Anti Smog: An Innovation Centre in Sustainable Development’ is a catalyst for cleaner air.

You’ve just installed energy- saving lightbulbs, only to hear that if one of them breaks you might have to evacuate the room to avoid toxic mercury. You’ve been sponsoring a patch of rainforest but now reports say the jungle is healing itself. You’ve been recycling your newspapers and glass bottles for years, but you’ve also bagged cheap flights for those lovely little city breaks. Guilty? Ashamed? Confused?Welcome to the world of green fatigue.

A plan has been submitted to cover a stretch of California highway with a 24-acre park. It would be built on a deck constructed over the below-grade portion of the Hollywood Freeway (US-101). Organizers argue that by placing a “cap” over one of the world’s most congested freeway systems, the necessary ventilation system would clean the air before re-circulating it back into the environment — creating a positive improvement in air quality for LA. Additionally, the park would also provide a nexus between East Hollywood and Central Hollywood–”alleviating the strain on the community from the initial creation of the freeway through this section of Hollywood.”

If art school was in our future we might opt to study under, or on top of, the amazing green roof at the School of Art, Design and Media at Nanyang Technological University in Singapore. This 5 story facility sweeps a wooded corner of the campus with an organic, vegetated form that blends landscape and structure, nature and high-tech and symbolizes the creativity it houses.